Incidence of tail structure distortions associated with dysplasia of the fibrous sheath in human spermatozoa

Abstract

Dysplasia of the fibrous sheath (DFS) is an anomaly found in spermatozoa of severe asthenozoospermic patients. Marked hypertrophy and hyperplasia of the fibrous sheath is the common characteristic. Immunocytochemistry allowed us to visualize the distortions and incidence of tail structure abnormalities associated with this phenotype in six patients; four with a complete form and two with an incomplete form of this pathology previously diagnosed and studied by electron microscopy. Microtubules and fibrous sheaths were studied using monoclonal antibodies against alpha-acetylated tubulin and anti-FSC1 (the major protein component of the fibrous sheath). Mitochondrial sheaths were visualized using the mitochondrion-specific vital dye MitoTracker green FM(TM). Phase contrast and fluorescent microscopy of semen samples showed large numbers of spermatozoa with short, rigid, thick and irregular tails. As expected, anomalous and completely distorted fibrous sheaths, severe alterations of the axonemal microtubules and different patterns of mitochondrial sheath configurations were found. While ultrastructural studies of thin sections allow an in-depth knowledge of the internal organization of the sperm tail, fluorescence labelling of selected sperm components affords a unique view of the whole flagellum including topographical relationships of various organelles. The combination of these different approaches is essential for a comprehensive understanding of this particular pathology.

The making of abnormal spermatozoa: cellular and molecular mechanisms underlying pathological spermiogenesis

“…c, d Reproduced from Turner et al (2001) with permission. e-g Reproduced from Rawe et al (2001) with permission profiles offer a window to developmental and differentiation events during spermiogenesis under normal conditions and in teratozoospermia.…”

Fibrous sheath of mammalian spermatozoa

“…Patients with dysplasia of the fibrous sheath (DSF) have sperm with short, rigid, and immotile flagella with hypertrophic and disorganized fibrous sheaths (e.g., Rawe et al, 2001). Some of the sperm have intact axonemes, but the microtubule organization is distorted in most.…”

Altered ultrastructure of mitochondrial membranes is strongly associated with unexplained asthenozoospermia

“…Disorganized or absent mitochondria are described in association with dysplasia of the fibrous sheath (DFS) (2,4,13), whereas a shorter length of the MP and a reduced number of mitochondrial gyres were reported in the motile fraction of spermatozoa selected from a group of 10 patients with moderate asthenozoospermia compared to 10 control men (14). Undefined ultrastructural abnormalities of the mitochondrial sheath were more frequent in 61 asthenozoospermic ejaculates compared with nine fertile control men (15), and these abnormalities represented an isolated defect in 7 of 25 sperm samples with absent forward motility (16).…”